6.6-stable review patch. If anyone has any objections, please let me know.
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From: Patryk Duda patrykd@google.com
commit df615907f1bf907260af01ccb904d0e9304b5278 upstream.
The cros_ec_get_host_command_version_mask() function requires that the caller must have ec_dev->lock mutex before calling it. This requirement was not met and as a result it was possible that two commands were sent to the device at the same time.
The problem was observed while using UART backend which doesn't use any additional locks, unlike SPI backend which locks the controller until response is received.
Fixes: f74c7557ed0d ("platform/chrome: cros_ec_proto: Update version on GET_NEXT_EVENT failure") Cc: stable@vger.kernel.org Signed-off-by: Patryk Duda patrykd@google.com Link: https://lore.kernel.org/r/20240730104425.607083-1-patrykd@google.com Signed-off-by: Tzung-Bi Shih tzungbi@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/platform/chrome/cros_ec_proto.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/platform/chrome/cros_ec_proto.c +++ b/drivers/platform/chrome/cros_ec_proto.c @@ -805,9 +805,11 @@ int cros_ec_get_next_event(struct cros_e if (ret == -ENOPROTOOPT) { dev_dbg(ec_dev->dev, "GET_NEXT_EVENT returned invalid version error.\n"); + mutex_lock(&ec_dev->lock); ret = cros_ec_get_host_command_version_mask(ec_dev, EC_CMD_GET_NEXT_EVENT, &ver_mask); + mutex_unlock(&ec_dev->lock); if (ret < 0 || ver_mask == 0) /* * Do not change the MKBP supported version if we can't